I would also look into the deal on the weight of the tent you like. There isn't that much scope for wild changes in the weight of tents. If there is a significant increase in the weight it could be something as simple as the weight is being honestly stated in current production or in a catalog you are looking at. Or is being weighed with poles/accessories in one place and not in another. I could also see you go through a whole custom project with someone and end up with an overweight tent. You only have to make some slightly different specification, and you will end up with more weight. It isn't like canoes, or something, where you can make them out of aluminum or leaded paint, on one extreme and corcell and carbon on the other, and play with weight in large amounts. To add a KG to a tent of the same design, it's pretty much attributable somehow to zipper weight, fabric weight, pole weight, etc...
Also, there is a high probability that if you buy some other tent on weight in preference to yours, you will find it is actually a pound or two heavier. Never become a slave to tent weights unless you have actually weighed them on a reliable scale yourself. Actually same goes for bikes. But at least with bikes the sizes are some excuse.